Skip to main content

More right-solid
More right-solid
SHOW DETAILS
eye
Title
Date Archived
Creator
A description of the plant, working on the Hampson process at the Bureau of Standards.
This paper discusses the results of a study of the effect of the rate of cooling upon the magnetic and other properties of an annealed eutectoid steel. In carrying out the experiment, six specimens of this steel were selected, heated to 800°C., and allowed to cool at various rates - one in air, another in lime, and the remainder in the furnace at slower and slower rates. The following properties were then measured: Normal induction for ordinary and large magnetising forces, residual induction,...
For several years the Bureau of Standards has been conducting grating measurements in red and infra-red arc spectra by the aid of specially sensitised photographic plates to improve the data in this region and to find some element which would furnish lines suitable for wave-length standards in this region. To the 25 elements already measured the following are here added: Silver, aluminium, gold, bismuth, cadmium, mercury, lead, antimony, tin, and zinc. The wave-length measurements are in the...
Gives the transmission curves from 0.6? to 3? of olive oil, cottonseed oil, peanut oil, tung oil, catfish oil, lard oil, fatty acids of linseed oil, pure linseed oil, oleic acid, glycerine, three samples of nitrocellulose, benzol, bakelite, paraffin oil, and selenite. As in previous investigations at greater wave-lengths, it is found that this region of the spectrum is also unsuitable for the spectroradiometric detection of animal and vegetable oils of similar composition. The spectroradiometer...
Gives the values of 50 wave-lengths in the spectrum of argon, 18 of krypton and 12 of xenon, obtained by comparison with the international primary standard by means of étalon interferometers. The error is considered to be of the order of 0.001 Å. in most cases. From wave-length measurements in argon and krypton frequency differences are obtained which are constant within the probable error of the measurements, thus giving further confirmation of the Combination Principle of Ritz. As the heavy...
The chief significance of this paper lies in the development and testing of an experimental method for determining an objective physical standard of 'white light.' The standard to be determined is the Planckian ('black-body') distribution of energy required to evoke the hueless sensation of brilliance, commonly called 'white' or 'grey,' under certain standard conditions stated in detail in the paper. Light from a lamp of known spectral distribution is modified by rotatory dispersion in a system...
The modulator tubes of radio-telephone transmitters used in commercial and military sets operate essentially as aperiodic power amplifiers of speech currents. The load on these tubes is determined approximately by the volt-ampere characteristics of the radio-generating circuit, as measured at its plate power-input terminals. At speech frequencies other effects occur as follows: (1) Current to the modulators and the generating circuit in parallel is supplied through an audio-frequency choke...
Contains the results derived from a study of the yellow, red, and infra-red regions of the arc spectra of yttrium, lanthanum, and cerium Spectrograms were photographed with the dyes pinacyanol, kryptocyanin, and dicyanin. The rare-earth compounds studied were derived from two sources: From the University of Illinois were obtained the oxalates of yttrium and lanthanum and the oxide of cerium, prepared under the direction of B.S. Hopkins; from Eimer and Amend were obtained the chlorides of...
Part 1 deals with the materials and construction of various spheres, and describes in detail the construction of a reinforced concrete sphere at the Bureau of Standards. It gives tests of the accuracy of integration by this sphere, the absorption of light by the sphere coating and by objects in the sphere, and the effect of the position of lamps. Proper methods of operation are also outlined. Part 2 gives a fairly complete resume of the general theory of the sphere, with the addition of a...
Specific volumes of pure ammonia under the pressure corresponding to saturation have been determined from -78° to 100° C. The method employed is similar to one previously used by Dieterici, and consists essentially in observing, at various temperatures, the volumes of the liquid and vapour phases in equilibrium in a closed vessel. The total mass of ammonia is given by M = [v/?] [(V-v)/u'], where u and u' are the specific volumes of liquid and vapour respectively, V the total volume of the...
The effective capacity of an inductance coil depends in general both on the capacities existing between parts of the coil itself and on the capacities existing between parts of the coil and the ground. On account of the importance of capacity effects in h.f. inductance coils, careful studies of these effects, both theoretical and experimental, have been made. An interesting result which has been found is that one effect seems to depend primarily on the capacity of the coil to earth. This effect...
This paper presents quantitative data on the spectral transmittancy of seven permitted food dyes in the ultra-viiolet, visible, and near infra red, from wave length 240 to 1360 millimicrons. The dyes studied were Naphthol Yellow S, Orange I, Ponceau 3R, Amaranth, Erythrosine, Indigo Disulpho Acid, and Light Green S F Yellowish. All of these show the properties of indicators and were, with the exception of Erythrosine, all dissolved in distilled water containing a sufficient amount of an H-ion...
The present investigation is a continuation of previous work on the spectrophotoelectrical sensitivity of various substances. At 20° C. the spectrophotoelectrical sensitivity curve of proustite has a slight maximum at about 0.61? and a marked sensitivity with a wide maximum (at about 0.3?) in the ultra-violet. At -170° C. the intrinsic spectrophotoelectrical sensitivity is greatly increased; but the max. reaction is confined mainly in a sharp maximum at 0.578?. No photoelectrical sensitivity...
This paper describes and discusses a new method for measuring color temperatures between 3000 and 4000 degrees absolute centigrade, and presents some data on the color temperature of the gas filled tungsten lamp and the carbon arc.